Investigations on the PNP-chelated diiron dithiolato complexes Fe2(μ-edt)(CO)4{κ2-(Ph2P)2NC6H4R} related to the [FeFe]-hydrogenase active site

The chemistry of the diiron dithiolato hexacarbonyl complex Fe-2(mu-edt)(CO)(6) (edt, 1,2-ethanedithiolate) has received special attention, largely because that its structure is similar with the active site of [FeFe]-hydrogenase. In order to enrich the chemistry of complex Fe-2(mu-edt)(CO)(6) and synthesize new hydrogen evolution catalysts, a new route to the diiron dithiolato hexacarbonyl complex Fe-2(mu-edt)(CO)(6) was described. Reaction of Fe-3(CO)(12) and Me3SiSCH2CH2SSiMe3 in the presence of Et3N at 80 degrees C afforded Fe-2(mu-edt)(CO)(6) in 90 % yield. Furthermore, reaction of Fe-2(mu-edt)(CO)(6) and aminodiphosphine ligands (Ph2P)(2)NC6H4R (R=-3-CCH, 4-CCH) produced the new PNP-chelated diiron dithiolato complexes Fe-2(mu-edt)(CO)(4){kappa(2)-(Ph2P)(2)NC6H4R} (1 and 2). All the complexes were characterized by elemental analysis, IR, NMR spectroscopy, and particularly for 1 and 2 by X-ray single diffraction analysis. In addition, the electrochemical results indicated that 1 and 2 could be considered as electrocatalysts for hydrogen evolution reaction.

Automated summary

The research focused on the chemical properties of the diiron dithiolato hexacarbonyl complex and explored its potential as a catalyst for hydrogen evolution. By synthesizing new complexes, characterizing them, and conducting electrochemical experiments, the study confirmed the catalytic activity of the complexes for hydrogen evolution.